Mond duval



MARP'IN LEONARD EDMOND DUVAL, OE PARIS, rnANonlissloNoR 'ro THE EivEs LILLE COMPANY, OE SAME PLACE,

PRESSURE-REGULATOR FOR AIR-BRAKES,

SPECIFICATION forming part of Letters Patent No. 510,635, dated December 12, 1893. lApplication led February 9, 1893. Serial No. 461,665. (No model.) Patented in France July 1'87, 1892. No. 223,047

l long trains of cars of the simultaneous action of the air-brakes. In order that the advantages which result should have their full effeet it is necessary that there should be in the train pipe, when the train is in motion and the brakes oma constant pressure or a pressure that varies within very narrow limits, since every uctuation may give rise to an untimely application of the brakes. In order to insure as much as possible this constant pressure many regulators have been devised, whose operation is satisfactory when applied to trains of from twenty to twenty-live carriages, (of the small size used on European railways) but which allow luctuations of pressure when the trains are composed of a larger number of vehicles.

The object of the present invention is to overcome this objection, or at least to modify it to a great extent. This object is accomplished by the construction shown in the accompanying drawings, 'in which- Figure lis a vertical section of my improvement, and Fig. 2, .is a side elevation.

The regulator is composed essentially ofa two-seated valve A', whose opening establishes a communication between chamber B (which is in constant communication with the main reservoir on the locomotive by pipe C) and chamber D (to which the train-pipe is connected); a diaphragm F receiving `air pressure from the train-pipe; a spring G which opposes the pressure in chamber D and is of such length that its tension shall notbe subject to material fluctuation under the move-y ments of the diaphragm; and a valve l-l for the escape into the atmosphere of the air in excess in the train pipe, when the pressure therein accidentally exceeds the normal pressure. The valve H comprises a single small contracted openingo (from one to two millimeters in sectional area) in the plug O said opening being normally covered by the lower end of the stem of valve A. For convenience of manufacture valve A has its upper seat a little larger than its lower seat, and it follows that the air pressure from the main reservoir has a tendency to lift this valve. The dierence of pressure on the two' faces of the valve is compensated by the spring N', the force of which is lproperly regulated in view of this difference and the mean pressure in the trainpipe, always greater than that of the auxiliary reservoir which it supplies. Plug O carried by its diaphragm is screwed into sleeve Y P which is free to slide in an cylinder Q fitted into the main casting forming the springchamber. l

The operation'is as follow-sz-When the air contained inV the train-pipe is at its normal pressure, valve A isY closed,yas well as the small relief valve Hf. As soon as a fall of pressure occurs in the pipe', the diaphragm F is forced upward by spring G', opening the admission valve A and holding it open until the normal pressure of the train pipe is restored, when'the diaphragm returns, closing the admission valve, the relief valve remaining closed during the operation described. In case the pressure in the train-pipe rises above the normal by leakage of the admission Valve the diaphragm would continue to descend, further compressing the spring. Valve H would then open and the air in excess would escape into the' atmosphere until thenormal pressure is restored, permitting the diaphragm to rise and close the relief valve, the valve A' remaining also closed. It is essential however to the successful operation of the valve H and consequently the relieving of excessive pressure in the train-pipe, that the opening O in said valve should be sufciently small to cause a very gradual reduction of the pressure in the train-pipe, otherwise a sudden reduction of pressure would involve a rushr of air to the air exit and consequently a fluctuation of pressure likely to cause an untimely application of the brakes. roo

The 4tension of the main spring Gf mustpbe regulated `'lgn'operly according to the pressure acting on 'the diaphragm F when the apparatus is in its normal condition. To regulate this tension an adjusting screw R is provided. The diaphragm may be metallic or of rubber or other flexible substance, or (asis common) may be replaced by a piston.

Having thus described my invention, what I claim is- In a regulator for air-brake systems, the combination of a casing containing two chambers, the first being in constant communication with the main air-reservoir and the other with the train-pipe, a main-valve between the two casings, a ilexible diaphragm in the second or low-pressure chamber, a spring acting upon said diaphragm in opposition to the 4pressure in saidchamber in communication a relief valve formed bylthestem ofthe mainvalve and normally closing said vent, substantially as described.

In testimony whereof I have signed this specification in the presence of two "subscrib- 3o ing witnesses. l

MARTIN LONARD EDMOND DUVAL.

Witnesses:

ROBT. M. HooPEn, JEAN VICTOR BARBANCE. 

